| Parameter |
Value |
| Designation |
C/2023 S2 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-10-15T09:03:22.020480Z |
| Orbit solution date (soln_date, UTC) |
2024-06-06T23:12:32Z |
| Obs used |
392 |
| NEO |
- |
| M1 |
14.500 |
| K1 |
25.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2023-09-28T23:40:21.590400Z |
| Discovery magnitude (MPC) |
15.15 o |
| Discovery observatory (MPC) |
W68 · ATLAS Chile, Rio Hurtado |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-10-11.0000000 |
| e |
0.99288676 |
| q (au) |
1.067716 |
| a (au) |
150.102592 |
| i (deg) |
20.485436 |
| Ω (om, deg) |
230.562176 |
| ω (w, deg) |
78.109160 |
| M (ma, deg) |
359.997654 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.113 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.113 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.998 |
| k |
1.000 |
| δ90 |
10.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
06:22:40.25 |
+10:21:29.8 |
HIP 30353 |
12.99 |
| 2026-09-20 12:00 |
06:22:42.77 |
+10:20:45.5 |
HIP 30353 |
12.05 |
| 2026-09-21 00:00 |
06:22:45.20 |
+10:20:01.1 |
HIP 30353 |
11.12 |
| 2026-09-21 12:00 |
06:22:47.53 |
+10:19:16.7 |
HIP 30353 |
10.20 |
| 2026-09-22 00:00 |
06:22:49.76 |
+10:18:32.3 |
HIP 30353 |
9.30 |
| 2026-09-22 12:00 |
06:22:51.91 |
+10:17:47.9 |
HIP 30353 |
8.41 |
| 2026-09-23 00:00 |
06:22:53.95 |
+10:17:03.4 |
HIP 30353 |
7.53 |
| 2026-09-23 12:00 |
06:22:55.91 |
+10:16:18.9 |
HIP 30353 |
6.67 |
| 2026-09-24 00:00 |
06:22:57.76 |
+10:15:34.4 |
HIP 30353 |
5.82 |
| 2026-09-24 12:00 |
06:22:59.53 |
+10:14:49.9 |
HIP 30353 |
4.98 |
| 2026-09-25 00:00 |
06:23:01.19 |
+10:14:05.4 |
HIP 30353 |
4.15 |
| 2026-09-25 12:00 |
06:23:02.76 |
+10:13:20.9 |
HIP 30353 |
3.34 |
| 2026-09-26 00:00 |
06:23:04.24 |
+10:12:36.4 |
HIP 30353 |
2.56 |
| 2026-09-26 12:00 |
06:23:05.62 |
+10:11:51.9 |
HIP 30353 |
1.80 |
| 2026-09-27 00:00 |
06:23:06.91 |
+10:11:07.4 |
HIP 30353 |
1.13 |
| 2026-09-27 12:00 |
06:23:08.10 |
+10:10:22.9 |
HIP 30353 |
0.75 |
| 2026-09-28 00:00 |
06:23:09.19 |
+10:09:38.4 |
HIP 30353 |
1.04 |
| 2026-09-28 12:00 |
06:23:10.18 |
+10:08:53.9 |
HIP 30353 |
1.67 |
| 2026-09-29 00:00 |
06:23:11.08 |
+10:08:09.4 |
HIP 30353 |
2.38 |
| 2026-09-29 12:00 |
06:23:11.89 |
+10:07:24.9 |
HIP 30353 |
3.10 |
| 2026-09-30 00:00 |
06:23:12.59 |
+10:06:40.5 |
HIP 30353 |
3.83 |
| 2026-09-30 12:00 |
06:23:13.20 |
+10:05:56.1 |
HIP 30353 |
4.56 |
| 2026-10-01 00:00 |
06:23:13.71 |
+10:05:11.6 |
HIP 30353 |
5.29 |
| 2026-10-01 12:00 |
06:23:14.13 |
+10:04:27.3 |
HIP 30353 |
6.01 |
| 2026-10-02 00:00 |
06:23:14.44 |
+10:03:42.9 |
HIP 30353 |
6.73 |
| 2026-10-02 12:00 |
06:23:14.66 |
+10:02:58.6 |
HIP 30353 |
7.45 |
| 2026-10-03 00:00 |
06:23:14.78 |
+10:02:14.3 |
HIP 30353 |
8.16 |
| 2026-10-03 12:00 |
06:23:14.80 |
+10:01:30.1 |
HIP 30353 |
8.87 |
| 2026-10-04 00:00 |
06:23:14.73 |
+10:00:45.9 |
HIP 30353 |
9.58 |
| 2026-10-04 12:00 |
06:23:14.55 |
+10:00:01.7 |
HIP 30353 |
10.29 |
| 2026-10-05 00:00 |
06:23:14.28 |
+09:59:17.6 |
HIP 30353 |
10.99 |
| 2026-10-05 12:00 |
06:23:13.91 |
+09:58:33.5 |
HIP 30353 |
11.70 |
| 2026-10-06 00:00 |
06:23:13.44 |
+09:57:49.5 |
HIP 30353 |
12.40 |
| 2026-10-06 12:00 |
06:23:12.87 |
+09:57:05.6 |
HIP 30353 |
13.10 |
| 2026-10-07 00:00 |
06:23:12.20 |
+09:56:21.7 |
HIP 30353 |
13.81 |
| 2026-10-07 12:00 |
06:23:11.43 |
+09:55:37.9 |
HIP 30353 |
14.51 |
| 2026-10-08 00:00 |
06:23:10.56 |
+09:54:54.1 |
HIP 30353 |
15.22 |
| 2026-10-08 12:00 |
06:23:09.60 |
+09:54:10.4 |
HIP 30353 |
15.93 |
| 2026-10-09 00:00 |
06:23:08.53 |
+09:53:26.8 |
HIP 30353 |
16.64 |
| 2026-10-09 12:00 |
06:23:07.37 |
+09:52:43.2 |
HIP 30353 |
17.35 |
| 2026-10-10 00:00 |
06:23:06.10 |
+09:51:59.8 |
HIP 30353 |
18.07 |
| 2026-10-10 12:00 |
06:23:04.74 |
+09:51:16.4 |
HIP 30353 |
18.79 |
| 2026-10-11 00:00 |
06:23:03.27 |
+09:50:33.1 |
HIP 30353 |
19.52 |